Investigation and management of hypertension

1. Investigation and management of hypertension http://www.abersychan.demon.co.uk/bp/BHSguide99.htm

2. Why detect and treat? • Most commonly • HT is a risk factor for cardiovascular disease, like smoking, DM, lipids. • Stroke, LVF, renal failure, MI • Less commonly • A medical emergency

3. Classifications • Aetiology • Essential • Secondary • Prognostic • Benign • Accelerated Most cases Usually no symptoms (Implications for compliance) A chance finding The need for screening Unusual May be symptoms related to the disease Probably commoner in younger patients Important for prognosis Benign v accelerated decided on examination of the fundi Massively commoner than accelerated Fundi grades I and II ‘Benign’ is a misnomer! Still causes stroke Rare Medical emergency (Pre-eclampsia) Fundi grades III and IV

4. Symptoms, signs and tests. • Look for consequences • Fundi, LVH. • Look for secondary causes • Kidneys, endocrine etc. • Look for co-morbidities • DM, hyperlipidaemia, smoking, alcohol

5. Secondary causes • Renal • Polycystic kidneys • Glomerulonephritis • Chronic pyelonephritis • Endocrine • Cushings • Acromegaly • Adrenaline-secreting tumour • Aldosterone secreting tumour • Vascular • Coarctation • Renal artery stenosis • Metabolic • Hypercalcaemia (commonly hyperparathyroidism)

6. How to diagnose and assess • You are interested in sustained HBP. • So take several recordings over several weeks. • And supplement this with 24-h BP monitoring • Look for LVH: CXR and ECG • Measure renal function • Investigate co-morbidities: sugar cholesterol.

7. How to diagnose and assess • You are interested in sustained HBP. • So take several recordings over several weeks. • And supplement this with 24-h BP monitoring • Look for LVH: CXR and ECG • Measure renal function • Investigate co-morbidities: sugar cholesterol.

8. How to diagnose and assess • You are interested in sustained HBP. • So take several recordings over several weeks. • And supplement this with 24-h BP monitoring • Look for LVH: CXR and ECG • Measure renal function • Investigate co-morbidities: sugar cholesterol.

9. How to diagnose and assess • You are interested in sustained HBP. • So take several recordings over several weeks. • And supplement this with 24-h BP monitoring • Look for LVH: CXR and ECG • Measure renal function • Investigate co-morbidities: sugar cholesterol.

10. The patient needs to know what you are doing • S/he has no symptoms but your drugs may provide them! • S/he may think the drugs are a cure, when they are not. • S/he may be unaware of the risks of HBP, so stress what you are trying to prevent. • Stress life-style changes that will help.

11. When to treat • >150/90 (or > 140/80 in a diabetic). • But BP varies from visit to visit. • Diastolic, systolic or MAP? • You need to come to an opinion that there is sustained HBP, and that the benefits of treatment outweigh the risks.

12. What drugs? • ACE-inhibitors • A2 receptor antagonists • Beta blockers • Thiazides • Calcium antagonists

13. How they work • Reduce cardiac output • Reduce venous return • Venodilators • Salt + water loss • Reduce stroke volume • Beta blockers • Reduce peripheral resistance • Arteriodilators

14. How to use them • Use one drug if you can. • Start with a low dose and build up to maximum (BNF). • Monitor response, and look for ADRs. • Add a second drug if you need to. • Add a third drug if you need to. • Remember that failure to respond might equal non-compliance.

15. ACE inhibitors • Angiotensin-II is a vasoconstrictor and stimulates aldosterone release (salt/water retention). • CAUTIONS • Renal impairment • First dose hypotension • Generally well tolerated, but cough is common • Ramipril.

16. Angiotension receptor antagonists • Compete with A-II for the receptor. • CAUTIONS • These are relatively newer drugs. Not all ADRs may yet be known. • Renal dysfunction. • Cough is not a problem. • Losartan.

17. Beta blockers • 1 receptors – myocardium – increased force of contraction. • 2 receptors – vascular smooth muscle – relaxation (vasodilatation). • Net result: reduced stroke volume and vasoconstriction in some places. • CAUTIONS • Asthma and bronchitis • PVD • Heart failure • Atenolol

18. Thiazide diuretics • Salt and water loss, but probably also vasodilatation. • CAUTIONS • Gout • Hypokalaemia • Impotence • Increased sugar • Bendrofluazide.

19. Calcium antagonists • Arteriodilators and reduced stroke volume • Often poorly tolerated • Ankle swelling • Facial flushing • Headache • Nifedipine.